PCB double-sided boards have wiring on both sides. However, to use wires on both sides, it is necessary to have appropriate circuit connections between the two sides. The 'bridge' between these circuits is called a guide hole (via). A guide hole is a small hole filled or coated with metal on a PCB that can be connected to wires on both sides. Because the area of a double-sided board is twice that of a single panel, and because the wiring can be interleaved (which can be wound to the other side), it is more suitable for use in more complex circuits than a single panel. Strictly speaking, a double-sided board is a very important type of PCB board in the circuit board, and its purpose is very large. It is also easy to see if a PCB board is a double-sided board. I believe friends can fully grasp the understanding of a single panel. A double-sided board is an extension of a single panel, meaning that the circuit of a single panel is not enough to switch to the opposite side. Another important feature of a double-sided board is that it has through holes. Simply put, it means double-sided wiring, with lines on both sides! In summary, a board with double-sided wiring is a double-sided board! Some friends may ask, for example, if a board runs on both sides, but only one side has electronic components, is it a double-sided board or a single panel? The answer is obvious, such a board is a double-sided board, only with parts installed on the board of the double-sided board.